Internal low energy atrial cardioversion: efficacy and safety in older patients with chronic persistent atrial fibrillation.

BACKGROUND

Low-energy internal atrial cardioversion is a relatively new technique based on delivery of intracardiac shocks through transvenous catheters placed into the atria or the vessels.

OBJECTIVE

The aim of this study was to assess in older and younger patients with chronic persistent atrial fibrillation (AF) the efficacy and safety of transvenous low-energy internal atrial cardioversion performed without routine administration of sedatives or anesthetics.

DESIGN

A prospective longitudinal study.

SETTING

A cardiological university hospital.

PARTICIPANTS

82 patients, divided into older (> or = 60 years) (n = 49) and younger (n = 33) subjects.

MEASUREMENTS

Atrial defibrillation threshold for internal cardioversion, measured as leading edge voltage (V) and delivered energy (J) of effective shocks, percentage of patients maintaining sinus rhythm at short-term (within 3 days) and at long-term follow-up.

METHODS

Patients with chronic persistent AF, treated with oral anticoagulants for at least 3 to 4 weeks, were admitted to hospital. Following a clinical work-up, patients were subjected to low-energy internal atrial cardioversion with shock delivery according to a step-up protocol.

RESULTS

Internal cardioversion was effective in restoring sinus rhythm in 90% (44/49) of the older patients and in 94% (31/33) of the younger patients. Shocks were effective at a mean energy between 6 and 8 joules (range 0.9-23) and administration of sedatives or anesthetics was required during the procedure in 22% (11/49) of older and in 48% (16/33) of younger patients (P = .026 at chi-square). No major complications occurred during the procedure. Pharmacological prophylaxis of AF recurrences was instituted immediately following the procedure. During inhospital stay and during the follow-up (mean 12 +/- 9 months for older patients and 15 +/- 10 months for younger patients), AF recurred in 39% (17/44) of older patients and in 16% (5/31) of younger subjects (P = .064 at chi-square).

CONCLUSIONS

Internal low energy cardioversion is a very effective procedure for restoring sinus rhythm in patients with AF; it can be performed in older patients, and administration of sedatives or anesthetics can be avoided or minimized in a substantial proportion of subjects. Recurrences of AF in the long term tend to be higher in older subjects and intensive prophylaxis with antiarrhythmic drugs is required.